A liquid droplet ejection apparatus comprises: a nozzle from which a liquid droplet is ejected; a pressure chamber filled with liquid to which a pressure is applied in order to eject the liquid in a form of the liquid droplet from the nozzle; and a supply port which supplies the liquid to the pressure chamber, wherein inertance Mn of the nozzle, resistance Rn of the nozzle, compliance Cn of a nozzle section due to surface tension, inertance Ms of the supply port, and resistance Rs of the supply port satisfy the following two formulas: